Can someone explain a bit further the AD referred to in UNCTUOUS's post?
The investigation revealed that water can accumulate in the Ps3 and P3B pressure sensing system, which can freeze in the full authority digital engine control (FADEC) sensing ports or pressure line. Frozen water can result in a restriction or a blocked signal to the FADEC. This blocked signal can cause a corruption of the FADEC signal and result in abnormal engine start characteristics on the ground or lack of engine response to commanded thrust levels in flight.
The AD goes on to say that the engines then continued to operate normally.
The five in-flight LOTC events were temporary in that the engine recovered and continued to operate normally for the remainder of the flight.
Since the incidents occurred at altitude, how could this be? Unless the ice melted at altitude, wouldn't the sensor continue to remain blocked, and the FADEC contiue to be fed corrupted data?
Is it assumed that the ice melted at altitude
after the LOTC event, or was a considerable loss of altitude and descent into warmer air involved?
If the engines were re-started at altitude, does the FADEC ignore the blocked Ps3 signal and the corrupted data, maybe through some sort of re-normalizing of sensors? (and what exactly is the Ps3 sensor measuring that when corrupted causes an engine roll-back?)